With the view of eliminating at least some of these drawbacks, the invention relates to a method for monitoring a control device of a fuel metering valve of an aircraft turbojet engine, the control device supplying a control current (FMV_CUR) to a servo valve in order to modify the position (FMV_POS) of the fuel metering valve, the method comprising:                a step for determining the position (FMV_POS) of the fuel metering valve during a flight of the aircraft;        a step for determining the travelling speed of the fuel metering valve;        a step for determining the control current (FMV_CUR) when the travelling speed of the fuel metering valve is zero;        a step for calculating a mean control current (FMV_CURM) when the travelling speed of the fuel metering valve is zero, the mean control current (FMV_CURM) forming an indicator of deterioration of the control device;        a step for comparing the deterioration indicator with a reference base of indicators with deterioration so as to infer the type of deterioration from it;        a step for calculating an abnormality score for the deterioration indicator;        a step for comparing the abnormality score with a decision threshold of abnormality characteristic of the type of deterioration; and        a step for releasing an alarm in case of violation of the decision threshold of abnormality.        
Thanks to the invention, it is possible to detect any deterioration of the control device of a fuel metering valve of a turbojet engine and characterize it. So, it is possible to detect whether the deterioration corresponds to a positive or negative drift of the control current.
Preferably, the deterioration indicator is normalized according to its standard deviation and average obtained over a plurality of flights during a learning phase. So, a relevant abnormality score that makes it possible to accurately characterize the type of deterioration is obtained.
According to a preferred aspect of the invention, the abnormality score of the deterioration indicator is a function of the absolute value of the said normalized deterioration indicator.
Preferentially, the reference base of indicators with deterioration comprises an indicator of deterioration of a positive drift and an indicator of deterioration of a negative drift.
According to an aspect of the invention, the method includes a step for comparing the evolution of the slope of the abnormality score with a threshold of maximal abnormality before failure. It is thus possible to advantageously foresee the term at which the failure is effectively going to arise. So, it is possible to make an early maintenance operation.
Preferably, the value of the threshold of maximal abnormality before failure is defined by learning during several no-deterioration flight cycles of an aircraft.